obstructed vehicle-to-vehicle channel modeling for ... v2v channel... · for the frequency band, 5...

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Wireless & Mobile Communication

for Rail Transportation (WiMiRT)

Obstructed Vehicle-to-Vehicle Channel Modeling for

Intelligent Vehicular Communications

Ke Guan, Bo Ai, Danping He, David W. Matolak, Qi Wang, Zhangdui Zhong, Thomas

Kuerner (E-mail: [email protected])

Beijing Jiaotong University, China; University of South Carolina, USA; Technische

Universitaet Braunschweig, Germany

Wireless & Mobile

Communication for Rail

Transportation (WiMiRT)

Outline

2

1. Motivation

2. Integrating V2V small-scale structures into ray-tracing simulator

3. Realistic V2V ray-tracing simulator for intelligent connected

vehicles

4. Ray-tracing simulations on obstructed V2V channels

5. Channel characterization

6. Verification with QuaDRiGa

7. Conclusion

2018/11/18

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Outline

3

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Motivation

4 2018/11/18

The vision of intelligent connected vehicles requires a seamless

low-latency and ultra-reliable vehicle-to-vehicle (V2V)

communication network.

Hence, V2V communications have drawn considerable attention

and made remarkable progress in recent years.

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Motivation

5 2018/11/18

5 GHz

For the frequency band, 5 GHz is of importance because two V2V communications

standards – IEEE 802.11p and ITS G5 – have been proposed for this band.

In order to address the challenges in intelligent vehicular communications, it is of

importance to investigate the V2V channel characteristics in the 5 GHz band

especially in the most challenging conditions, such as when shadowing induced by

vehicles obstructs the line-of-sight (LOS) between transmitter (Tx) and receiver (Rx)

of two communicating vehicles.

x

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Motivation

6 2018/11/18

To model V2V channels realistically, the influence of the main objects in the

environment must be considered.

The small-scale structures

such as traffic signs and

lamppost are the most

important scatterers in a

traffic congestion situation.

Thus, ray-tracing tools

have to take into account

multi-paths from both

large-scale and small-

scale structures.

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Motivation

7 2018/11/18

Another particular significant topic is how to incorporate the dynamic shadowing

effect of the vehicular obstruction.

Only when incorporating the obstructing vehicle effects via V2V channel

measurements, extensive RT simulations for such obstructed V2V channels can be

used to evaluate candidate intelligent vehicular communication schemes in

challenging conditions.

x

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Motivation

8 2018/11/18

In this paper, we stochastically model the obstructed V2V channels in the 5-GHz

band through measurement-validated RT simulations in terms of:

Path loss (PL)

Shadow fading (SF)

Delay dispersion

For the latter, we provide root-mean-square (RMS) delay spread (DS) results.

We also provide small-scale fading Rician K-factor (KF), spatial information in

terms of:

Azimuth angular spread of arrival/departure (ASA/ASD)

Elevation angular spread of arrival/departure (ESA/ESD)

Cross-polarization ratio (XPR)

The cross-correlations among several parameters

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Motivation

9 2018/11/18

Workflow of obstructed V2V channel

modeling for intelligent vehicular

communications

1. The radar cross sections of the

small-scale structures are integrated

into RT tools through a general

framework.

2. We calibrate the EM and scattering

parameters of the large-scale

structures through measurements.

3. The shadowing effects of the

obstructing vehicles are incorporated

in the RT tool.

4. After this integration and calibration,

extensive RT simulations are

conducted.

5. Based on the RT results, the target

channel is characterized and input

into and verified by the 3GPP-like

quasi deterministic radio channel

generator (QuaDRiGa).

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Outline

10

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Integrating V2V small-scale structures into RT simulator

11 2018/11/18

The most relevant propagation mechanism of the small-scale structures in V2V

environments is not reflection, but scattering.

In RT tools, the electric field intensity of the ray scattered from the small-scale

structure can be expressed as:

The radar cross section of the small-scale structure, which is a measure of how

much electromagnetic energy is scattered from an object.

The small-scale structures can be integrated

into V2V RT simulators through modeling

their radar cross section with a framework

detailed in our recent publication [A].

Through this framework, we integrate three

types of typical traffic signs into an in-house

developed RT simulator.

[A] K. Guan, B. Ai, M. L. Nicol as, R. Geise, A. Moller,

Z. Zhong, and T. K urner, “On the influence of

scattering from traffic signs in vehicle-to-x

communications,” IEEE Transactions on Vehicular

Technology, vol. 65, no. 8, pp. 5835–5849, Aug. 2016.

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Outline

12

1. Motivation



vehicles




7. Conclusion

2018/11/18

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High-Performance Ray-Tracing Platform -- CloudRT

13

3D environment modeling and antenna modeling

Parameter configuration for frequency,

propagation mechanisms, snapshot, etc.

Ray optical method

2

1

, k k

N tj f t t

k k

k

h t a t e t

J. Nuckelt, et al., “Deterministic and stochastic channel models implemented in a physical layer simulator for Car-to-X

communications,” 2010 Advances in Radio Science, 2010.

Ray-tracing methodology

2018/11/18

Accurate method:

• Image theory

Accelerating techniques:

• Space division

• Back face cut (BFC)

• Multi-core computing

• High-performance

platform

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14

Output of ray-tracing simulation platform

2018/11/18

Types (Directed, reflected, scattered, diffracted), Reflection order, Time of arrival, Distance, Field

intensity, Path loss, azimuth AoD and AoA, elevation AoD and AoA

Parameters are record for each ray, including:

Spatio-temporal-frequency

channel simulation result

Traced rays

Many channel characteristics can be calculated

Loss and fadingReceived power

Rician K-factor

Power delay profile RMS delay spread

Angular power spectrum RMS angular spread

Doppler spectrum RMS Doppler spread / mean Doppler shift

Time-varying property Coherence time

Polarization

Cross-correlation coefficient

Cross polarization discrimination (XPD)

Co-polarization power ratio (CPR)

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15 2018/11/18

http://raytracer.cloud/

Danping He, Bo Ai, Ke Guan (corresponding author), et al. “The Design and Applications of High-Performance Ray-Tracing Simulation

Platform for 5G and Beyond Wireless Communications: ATutorial,” to appear, IEEE Communications Survey and Tutorial, 2018.

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Realistic V2V RT simulator for intelligent connected vehicles

16 2018/11/18

RT calibration on large-scale structures The differences of

the mean path loss

are less than 1 dB

The mean delay

spread differences

are less than 1 ns

It indicates that the

environment and

the EM parameters

of materials are

correct.

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Realistic V2V RT simulator for intelligent connected vehicles

17 2018/11/18

Incorporation of obstructing vehicle

The mean value of the shadowing attenuation for measurement and RT is 8.22

dB and 8.28 dB, respectively.

The values of standard deviation are 6.96 dB and 7.15 dB, respectively.

Thus, the RT agrees very well with the measurement without conducting any

dedicated calibration of the car material.

Comparison of the

shadowing of the truckThe truck and its corresponding 3D model

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Outline

18

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Ray-tracing simulations on obstructed V2V channels

19 2018/11/18

The Tx and Rx in RT simulations are deployed on the roofs of oncoming cars

driving in opposite directions in the urban environment.

The starting distance between the Tx and Rx is 300 m.

A truck is in front of the Tx car, and the distance between them is kept at 5 m.

The vehicles move at the same speed, the moving step of each snapshot is 1 m.

We perform 100 different simulations, in each of which, 5-10 traffic signs are

randomly generated along the road sides.

After the RT simulations, the statistical results of key channel parameters are

obtained.

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Outline

20

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Channel characterization

21 2018/11/18

Channel parameters

Cross-correlation between key parameters

The power relation of the MPCs

changes faster than does the SF, DS

and KF.

The KF is negatively correlated with

the other parameters.

The correlation distances of the

angular spreads are larger than those

of the other parameters.

The ASA and ASD, as well as the

ESD and ESA are highly correlated.

The XPR results indicate that

substantial de-polarization takes

place in this channel, and therefore,

dual-polarized antenna configurations

are recommended.

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Outline

22

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Transportation (WiMiRT)2018/11/1823

Verification with QuaDRiGa

Comparison of path loss and shadow fading between

QuaDRiGa and RT

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Outline

24

1. Motivation



vehicles




7. Conclusion

2018/11/18

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Transportation (WiMiRT)2018/11/1825

Conclusion

Based on an in-house-developed realistic V2V RT simulator, obstructed

V2V channels in the 5-GHz band were characterized and modeled.

All the parameters are input into and verified to generally agree with those

of the 3GPP-like channel generator (QuaDRiGa).

Good agreement indicates that the two parameter tables presented in this

paper and the obstructed V2V modeling can be incorporated into standard

channel model families.

The result of this study provides a baseline for system design and

evaluation of intelligent vehicular communications in these challenging

conditions.

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Thank you

for your attention.Ke GUAN Ph.D. Associate Professor Ph.D. Supervisor

Alexander von Humboldt Research Fellow

URSI Young Scientist Awardee

Deputy Director of Modern Communication Institute

State Key Laboratory of Rail Traffic Control and Safety

Beijing Jiaotong University, Beijing, China Postcode: 100044

Email: [email protected], [email protected], [email protected]

Mobile: +86-13810331547

Personal website: http://sites.google.com/view/keguan/

Research group website: http://raytracer.cloud/

obstructed vehicle-to-vehicle channel modeling for ... v2v channel... · for the frequency band, 5...

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